JIVE TURKEY,
first off, if you don't have one go buy a tach. That is what your going to need, to set this motor. If your not familiar w/ a 4stroke you will end up buring it up trying to set it by your ear. Get a tach. Your fuel is OK. I use bryon YS 20/20. I am also using a OS "F" plug.

Here is how you set the high end. Get a tach. Open it up about 2 1/2 turns. Start motor. let it warm up for about 30 seconds or so. Take off glow starter. slowly advance throttle to full throttle, while holding plane of course. then start leaning it out. Take it up to peak RPM then back it off about 800RPM.

Then I would run 2 tanks thru it at that setting on ground. Let it idle for a while, advance throttle to midrange, for a while, then run it at full throttle for about 30 seconds. Then take it back to idle and do it again.

Then after 2 tanks, then Full throttle peak it out then back it off about 800RPM, go fly it like this for the rest of the day. Before each flight check peak it out then back it off about 800. It will take about 1 gallon or so to break in this engine. After about 1 gallon you can run it off of peak about 500RPM. After your break it in. Set your needle the first of the day, then leave it alove for the rest of the day.

Dave Shadel is the YS GURU. Listen to him. I learned a ton of info about my YS63.

I am turing a 13x6APC at 11,400 peak here in memphis, TN. I set it to fly about 10,800.